lengthvalidator.cs

一个ASP.NET下的中文内容管理和社区系统

namespace ASPNET.StarterKit.Communities {
    using System;
    using System.Web.UI;
    using System.Web.UI.WebControls;

    //*********************************************************************
    //
    // LengthValidator Class
    //
    // Derived class from custom validator that checks length of input.
    //
    //*********************************************************************
    public class LengthValidator : CustomValidator {


        //*********************************************************************
        //
        // MaxLength Property
        //
        // The Maximum Length that a user is allowed to enter.
        //
        //*********************************************************************
        public int MaxLength {
            get {
                if (ViewState["MaxLength"] == null)
                    return 0;
                else
                    return (int)ViewState["MaxLength"];
            }
            set { ViewState["MaxLength"] = value; }
        }


        //*********************************************************************
        //
        // OnPreRender Property
        //
        // This is where we add the client-side script.
        //
        //*********************************************************************
    	override protected void OnPreRender(EventArgs e) {
		    base.OnPreRender(e);
		    if (RenderUplevel) {
			     if (!Page.IsStartupScriptRegistered("validateLength")) {

		         string validateLength = "<script language=\"JScript\">" 
		          + "function validateLength(source, arguments) { "
		          + "if (arguments.Value.length > " + MaxLength + ") "
		          + "  arguments.IsValid = false; "
		          + "else "
		          + "  arguments.IsValid = true; } "
		          + "</script>";

			      Page.RegisterStartupScript("validateLength", validateLength);
                }
            }
        }


        //*********************************************************************
        //
        // OnServerValidate Method
        //
        // Server-side function for checking length.
        //
        //*********************************************************************
        override protected bool OnServerValidate(string value) {
            if (value.Length > MaxLength) 
                return false;
            else
                return true;
        }



        //*********************************************************************
        //
        // LengthValidator Constructor
        //
        // Assign the client validation function.
        //
        //*********************************************************************
        public LengthValidator():base() {
            ClientValidationFunction = "validateLength";
        }



    }
}